This application is in response to CREG announcement number DCCP-17, "Malignancy Induced by Small DNA Viruses (Adenoviruses or Papovaviruses)," April 1, 1976. We propose to study the transcription of virus specific RNA in cells transformed by temperature sensitive mutants of polyoma virus. The objective of these experiments is to determine whether virus coded proteins influence the expression of viral genes in transformed cells. Several lines of evidence suggest that the abnormal small virion proteins coded for by the ts3 and ts59 polyoma mutants can block or reduce transcription of polyoma-specific RNA during lytic infection at the restrictive temperature. We will investigate whether similar effects on transcription occur in cells transformed by these mutants, perhaps accounting for the temperature dependent growth properties of cells transformed by the ts3 mutant. We will examine the transcription of early viral RNA in cells transformed by polyoma tsA mutants to determine whether an abnormal T-antigen affects transcription in polyoma-transformed cells. We will also examine the topology of the integrated viral genomes in polyoma transformed cells to determine whether the arrangement of virus specific sequences is similar in wild type and mutant transformed cells, and whether the arrangement is related to patterns of transcription of virus specific DNA.